Lately I have been asked a lot of questions about cameras, which one to buy and what the difference is between a full-frame camera vs. a crop-sensor camera. SO I decided to spell it out simply so you can understand the difference between cameras that have a full-frame sensor and a crop-frame sensor.
On a full-frame camera (a camera with a full-frame sensor) this is referring to a sensor-size that is equal to 35mm film. In other words, the rectangular sensor that captures your image will record the same area as 35mm film will (roughly 24mm x 36mm).
A cropped-sensor refers to any camera that has a smaller sensor than that of a full-frame camera. Most entry-level cameras have this cropped sensor. If you were to take the same photo with a full-frame camera, using the same lens from the same distance as a crop-frame camera, the cropped-frame camera would capture a smaller field of view; this means a smaller piece of the scene projected by your lens. The full-frame camera will get more of the edges of the same scene, or more 'real-estate'.
You can see the difference in the example below. The image on the left was taken with a Canon 5D Mark III and the image on the right, a Nikon D7000. Both cameras had a 50mm lens, shot with an aperture of f/2.8 and were taken from the same spot (the same distance from the dog).
Every cropped-sensor camera has a crop factor of either 1.3 x, 1.5x or 1.6x (the field of view gets smaller). This means your sensor will be a smaller version of a full-frame sensor.
Let's take a look at what each option has to offer to figure out which one is right for you.
Full-Frame
A full frame sensor will give you better performance in low light scenarios, allowing you to have a better ISO performance at high ISO numbers. They also give you a little better image quality than a crop sensor. This is why they are considered "professional camera bodies" and most professional photographers pick full-frame cameras over cropped. Full-frame also allows a wider-angle of view which can be helpful for things like landscape or architectural photography. A full-frame DSLR will also give you a slightly more shallow depth-of-field than a crop sensor DSLR.
Advantages:
Better low light performance
Shallower depth of field
Better dynamic range
Wider angle of view
Cropped-Frame
Having a cropped sensor will lose that extra 'real-estate' in your photo. With a wide-angle lens on a crop-sensor camera, you won't get the widest field of view like you would with a full-frame camera. On the other hand, a crop-sensor DSLR paired with a telephoto lens will give you more distance from this smaller field of view. For example, if you have a 200mm lens on a crop-sensor camera, you apply the 1.5x crop factor to the lens (200 x 1.5 = 300). This would really get you 300mm focal length for the subject you are shooting, or in other words, FREE ZOOM! This can be very beneficial for shooting subjects that are far away, such as getting closer shots of an athlete in a sporting event or for wildlife photography. We'll talk more about the crop factor and lenses later on.
Advantages:
More affordable
Wider range of lens selection
Increased focal length
Lighter and smaller